Removing some of the elements from vibe.core.concurrency.Future[] futurelist

[Nicholas Wilson]

On Saturday, 28 October 2017 at 13:51:42 UTC, kerdemdemir wrote:
> I am trying to make non blocking web requests to a web service.
>
> vibe.core.concurrency.Future!(UserData)[] futurelist;
>
> // I will make http requests in for loop and push them to 
> futureList
> foreach( elem; elemList )
> {
>         // In makeWebRequest I make the httprequest, parse json 
> and push to my UserData
>         auto future = vibe.core.concurrency.async( 
> &elem.makeWebRequest );
>         futurelist ~= future;
> }
>
>
> // I want to do call ProcessResponceData for each future which 
> is ready.
> while ( futurelist.length > 0 )
> {
>         futurelist.filter!(a => a.ready()).each!(a=> 
> ProcessResponceData(a.getResult()));
>
>         //!!!!!  Here is my problem
>         //!!!!!  I want to remove the futures which are already 
> processed.
>         futurelist = futurelist.filter!(a => !a.ready()).array;	
>         sleep(10.msecs);
>
> }
>
> I am having troubles while trying to remove the future which I 
> already processed.
>
> futurelist = futurelist.filter!(a => !a.ready()).array;	 
> results with:
>
> /usr/local/bin/../import/std/array.d(2716,20): Error: can't 
> have array of nothrow @safe void()
> /usr/local/bin/../import/std/array.d(2782,46): Error: can't 
> have array of inout nothrow @safe void()
> /usr/local/bin/../import/std/array.d(3158,1): Error: template 
> instance std.array.Appender!(Future!(UserData)[]) error 
> instantiating
> /usr/local/bin/../import/std/array.d(133,32):        
> instantiated from here: appender!(Future!(UserData)[])
>
> futurelist = futurelist.filter!(a => !a.ready());	 results with:
>
>  Error: cannot implicitly convert expression 
> (filter(futurelist)) of type FilterResult!(__lambda5, 
> Future!(UserData)[]) to Future!(AnalyzeData)[]
>
> Do you have any suggestion or workaround for my case?
> What lesson I should learn from this case? Do you guys have any 
> idea why I am getting those compile errors?
>
>
> Thanks
> Erdem

I'd take a look at why the error message says
`Future!(UserData)[]) to Future!(AnalyzeData)[]`
is AnalyzeData  the type returned by ProcessResponceData?

Alternatively you could use a singly linked list and splice out 
elements that pass the filter predicate. I think you'd have to 
roll your own though.